1. Field of the Invention
The present invention relates to a high speed upward flow filtration apparatus which an implements a high speed and high performance filtration by providing a filter layer comprising a plurality of fibrous lumps with a uniform thickness, and raising water having fine solid materials to pass through the filter layer.
2. Description of the Prior Art
An apparatus for filtering a stream in a channel is well known in the art as disclosed in Japanese Patent Laid-open No. 1-249113. The conventional filtration apparatus has the following construction as shown in FIG. 14. Water streams from upstream of a channel 11 via a water inlet 12 into a lower chamber 15 which is disposed between a channel bottom 13 and a lower perforated panel 14. The water upwardly streams via the lower perforated panel 14 and an upper perforated panel 16. The upward flow causes each fibrous lump to upwardly float toward the upper perforated panel 16 to form a fibrous lump filter layer 17 under perforated panel 16. As a result, the upward flow is filtered by passing through the fibrous lump filter layer 17.
Fine solid materials in the upward flow adhere to the fibrous lumps 5 in the lower layer of the fibrous lump filter layer 17 as filtration is performed. If a certain amount of the fine solid materials adhere to the fibrous lumps 5, the fibrous lumps 5 can not form the fibrous lump filter layer 17 due to an increased apparent specific gravity of the fibrous lumps 5. Accordingly, the fibrous lumps 5 float in an allowable floating/falling space for fibrous layer 18 or fall on the lower perforated panel 14. Therefore, fresh fibrous lumps 5 are always exposed at the lower portion of the fibrous lump filter layer 17. A filter bed has a horizontal surface to continue the upward flow filtration with lower pressure loss.
Stream velocity can be improved by lowering a vertical movable diaphragm 19 onto a fixed diaphragm 20 when the quantity of running water in the channel 11 is decreased.
In the conventional channel stream filtration apparatus, the fibrous lumps 5 including the fine solid materials in the upstream water have an increased apparent specific gravity. The fibrous lumps 5 float in the allowable floating/falling space for fibrous layer 18 or fall on the lower perforated panel 14 to continue the upward flow filtration with lower pressure loss and to expose the fresh fibrous lumps 5 continuously.
Accordingly, there are disadvantages in that the stream causes the fine solid materials adhering to the floating or falling fibrous lumps 5 to separate from the fibrous lumps 5, and the fine solid materials may pass through the fibrous lumps 5 of the thinned fibrous lump filter layer 17.
Further, in the conventional filtration apparatus, the vertical movable diaphragm 19 should be operated according to the quantity of the stream to increase the velocity of the upward flow. Thereby, the fibrous lump filter layer 17 can be formed. As a result, a complicated operation is required for the vertical movable diaphragm 19.